Previously known form tools preferably used for shaping thin-walled web-shaped or plate-shaped starting material containing at least a fiber material component, have the starting material shaped by simultaneous or alternate application of pressure and heat. In so doing, it is absolutely necessary that the gap width remaining between the male mold and female mold when the form tool is closed and kept absolutely uniform along the entire contour or that it follow contours drawn beforehand.
According to a known method for the production of such form tools, particularly those with a form surface formed by perforated sheet metal, the two halves of the tool, male mold and female mold, of such form tools are produced in such a way that a tap model is, taken from an original model or in such a way that a tap model is prepared from a model drawing, wherein the tap model forms a mold exactly true to the shape of the original mold, i.e., a positive mold. The perforated sheet metal forming the form surface of the tool is tapped or shaped over the pastime mold until it forms a replica of the surface contour of the tap model which is completely true to shape. The perforated sheet metal forming the form surface is then removed from the tap model and connected with a circumferentially extending frame or housing body, and reinforcements, e.g. in the form of sheet metal webs or the like are arranged in a grid-like manner and are to be attached at its rear side if required and, are arranged simultaneously or subsequently, partially by means of welding or also with the use of other suitable connecting techniques.
Because of the properties of sheet metal and the spatially curved deformation of the sheet metal material forming the form surface, it is unavoidable that the sheet metal forming the form surface of the tool halves will spring up at first, at least in some places, after the removal of the tap model or that its desired contour will change in a comparable manner, so that an unwanted change in the contour of the form surface will naturally result. Further, partly because of the subsequent arrangement of the frame or housing body of the form half and partly to the subsequent connection of the reinforcements at the shaped perforated sheet metal forming the respective form surface, other distortions or changes in the shape of the perforated sheet metal take place, so that the form tool must be reworked in its entirety with respect to its dimensioning and the occurring changes in shape must be eliminated, accompanied by a considerable expenditure of work time.
Therefore, an object of the invention is to provide a manner of constructing a form tool and a method for the production of same which simplifies the production of the form tools from sheet metal material, in particular perforated sheet metal material, in such a way that the work expenditure for the preparation of the tool is reduced overall and, in particular, the expenditure for the reworking of the form surfaces on the finished tool which were prepared on the tap model is eliminated or at least limited to a practically negligible minimum.